AIM: To characterize the composition and functional features of the aqueous humor microbiome in common ocular diseases, including myopia, cataract, primary open angle glaucoma (POAG), and Posner-Schlossman syndrome (PSS). METHODS: We performed metagenomic sequencing on 176 aqueous humor samples from patients with cataract (n=37), POAG (n=66), PSS (n=35), and myopia patients (n=38, as controls). Taxonomic profiling, functional annotation, and diversity analyses were conducted to characterize microbial communities, with adjustments for age and gender where appropriate. Associations between microbial features and clinical parameters were evaluated using correlation analyses. RESULTS: We identified 6635 bacterial, 141 archaeal, 96 eukaryotic, and 108 viral operational taxonomic units (OTUs) in the aqueous humor. The microbiome was dominated by Actinomycetota and Pseudomonadota at the phylum level. Compared to myopia controls, POAG and PSS patients showed significantly reduced alpha diversity after age adjustment (P<0.05), whereas cataract patients showed no significant difference. Additionally, we identified disease-specific microbial signatures including enrichment of Cytomegalovirus (CMV) in PSS. Functional analysis revealed enrichment of distinct metabolic pathways. Finally, correlations were observed between microbiota/pathway abundance and clinical phenotype, though none remained significant after multiple testing correction. CONCLUSION: This study provides a preliminary characterization of the aqueous humor microbiome in patients with POAG, PSS, cataract, and myopia controls. The identified microbial signatures and functional pathways offer new insights into potential microbiome-mediated mechanisms in ocular pathophysiology and may inform future diagnostic and therapeutic strategies.

Deep learning (DL) methods utilize large numbers of images and annotating them is very labor-intensive. In contrast, in clinical practice such large numbers are not needed. Under the DL framework, how to integrate knowledge and data is unknown. We established an ensemble deep learning system (EDLS) that could integrate knowledge and data to automatically detect Glaucomatous Optic Neuropathy (GON), pathologic myopia and diabetic retinopathy using fundus images. An EDLS for the classification of GON was developed using 4225 fundus images obtained from Beijing Tongren Hospital. The generalization of the EDLS was tested on three testing datasets. Two EDLSs for the classification of pathologic myopia and diabetic retinopathy were developed and tested on two datasets obtained from websites respectively. For the classification of GON, the area under the receiver operating characteristic curve (AUC) of EDLS was 0.998 (95

AIM: To propose a novel glaucoma surgery for rebalancing translaminar pressure difference. METHODS: Three non-human primates with normal eyes and two with laser-induced glaucoma underwent the novel surgical procedure. Cannulation of the subarachnoid space was performed after completion of routine vitrectomy steps. An XEN 45 implant was inserted into the created puncture to communicate between the vitreous body and subarachnoid space. Intraocular pressure (IOP), fundus photography, and spectral-domain optical coherence tomography were assessed at baseline and regular intervals during follow-up. RESULTS: All operated eyes showed IOP reduction in the first postoperative month. Two (2/3) normal eyes and one (1/2) glaucomatous eye maintained lower IOP until 18mo after operation. The XEN 45 implant remained positioned through the lamina cribrosa in all normal eyes but was not detected in two glaucomatous eyes. Complications observed in this study included retinal vascular bleeding in 1/3 normal eyes and XEN implant dislocation in all 2 glaucomatous eyes. CONCLUSION: Subarachnoid space cannulation and mini-shunt implantation may contribute to IOP reduction, possibly by rebalancing translaminar pressure difference and enhancing aqueous humor drainage. The development of a suitable mini-shunt requires further investigation.

AIM: To investigate the role of adipokines in primary open angle glaucoma (POAG) by comparing the levels of these molecules in the aqueous humor among POAG patients and cataract patients with or without metabolic disorders. METHODS: In this cross-sectional study, aqueous humor samples of 22 eyes of POAG patients (POAG group), 24 eyes of cataract patients without metabolic disorders (cataract group), and 24 eyes of cataract patients with metabolic disorders (cataract+metabolic disorders group) were assessed for 15 adipokines by Luminex bead-based multiplex array. The correlation between aqueous humor adipokines and clinical indicators of POAG was analyzed and compared across the groups. RESULTS: The analysis revealed that the levels of adiponectin, leptin, adipsin, retinol-binding protein 4 (RBP4), angiopoietin-2, angiopoietin-like protein 4 (ANGPTL4), chemokine (C-C motif) ligand 2 (CCL2), interleukin-8 (IL-8), and interleukin-18 (IL-18) in the aqueous humor of the POAG group were significantly higher than those in the cataract group. Additionally, the level of angiopoietin-2 in the POAG group was higher than in the cataract+metabolic disorders group. However, no significant correlation was found between the levels of adipokines in the POAG group and intraocular pressure (IOP), severity of POAG, or the use of glaucoma medications. CONCLUSION: This study demonstrates significant differences in aqueous humor adipokine levels between POAG and cataract patients. The findings suggest that the levels of aqueous humor adipokines may reflect the inflammatory states in POAG and systemic metabolic abnormalities.

Background:This is the first comprehensive comparison between gonioscopy-assisted transluminal trabeculotomy (GATT) and GATT combined with ab interno canaloplasty (ABiC) in patients with OAG. Purpose:The purpose of this study was to compare the efficacy and safety of gonioscopy-assisted transluminal trabeculotomy (GATT) combined with ab interno canaloplasty (ABiC) with those of GATT alone in patients with open-angle glaucoma (OAG). Design:This was a retrospective, comparative case series. Participants:Patients with primary open angle glaucoma who underwent GATT (27 eyes in Group 1) or GATT + ABiC (26 eyes in Group 2) were included. Methods:Outcomes including intraocular pressure (IOP), glaucoma medications, and surgical complications were analyzed. Main outcome measures:Surgical success was defined in terms of IOP and medication use as follows: (1) a preoperative IOP > 21 mmHg and a postoperative IOP ≤ 21 mmHg with at least a 20% reduction from baseline with (qualified success) or without (complete success) glaucoma medications or (2) a preoperative IOP < 21 mmHg while taking 3 or more glaucoma medications and a postoperative IOP ≤ 21 mmHg with a reduction of more than two medications (qualified success) or with no medications (complete success). Results:At 12 months, the mean IOP was 14.8 ± 2.2 mmHg in Group 1 and 16.6 ± 2.3 mmHg in Group 2 (p = 0.008). The number of medications was 0.6 ± 1.0 in Group 1 and 0.9 ± 1.3 in Group 2 (p = 0.334). At 24 months, the mean IOP was 15.3 ± 2.0 mmHg in Group 1 and 15.5 ± 2.4 mmHg in Group 2 (p = 0.676). The number of medications was 0.5 ± 0.9 in Group 1 and 0.9 ± 1.1 in Group 2 (p = 0.197). The complete success rates were 63.0% in Group 1 and 50.0% in Group 2 (p = 0.16), and the qualified success rates were 81.5% in Group 1 and 76.9% in Group 2 (p = 0.51). Conclusion:The GATT procedure, with or without ABiC, is safe and effective in decreasing the IOP and the number of antiglaucoma medications used.

Disruption of the glymphatic system plays a vital role in pathogenesis of neurodegeneration in normal tension glaucoma (NTG). We evaluated the impairment of glymphatic system of NTG patients by diffusion tensor image analysis along the perivascular space (DTI-ALPS), and explored the correlation between the ALPS index and dysfunction of visual cortices in resting state. DTI-ALPS was applied to 37 normal controls (NCs) and 37 NTG patients. Multidirectional diffusivity maps and fractional anisotropy (FA) maps were reconstructed to calculate ALPS index. The Amplitude of low-frequency fluctuation (ALFF) in visual cortices (V1-V5) were calculated using resting-state fMRI. Clinical data and ALPS indexes were compared between the groups. Lateralization of ALPS indexes and differences in visual field of two eyes were analyzed. Subsequently, regression analyses between ALPS indexes and mean deviation (MD) values of bilateral eyes and ALFF of visual cortices were performed. The bilateral ALPS indexes of NTG patients decreased significantly. In NCs and NTG patients, ALPS indexes in right hemisphere were lower than that in left hemisphere. The right ALPS indexes of NTG patients were positively correlated with the MD values of the left eyes. In NTG patients, decreased ALFF was detected in right V1 and bilateral V2-5, and the left ALPS indexes were positively correlated with ALFF in bilateral V1, V2, V5, and right V3V area. The ALPS index decreased in NTG patients, correlated with visual defects and ALFF, indicating impairment of the glymphatic system and the potential to be a biomarker in the future.

Purpose:This study aimed to propose a new deep learning (DL) approach to automatically predict the retinal nerve fiber layer thickness (RNFLT) around optic disc regions in fundus photography trained by optical coherence tomography (OCT) and diagnose glaucoma based on the predicted comprehensive information about RNFLT. Methods:A total of 1403 pairs of fundus photographs and OCT RNFLT scans from 1403 eyes of 1196 participants were included. A residual deep neural network was trained to predict the RNFLT for each local image in a fundus photograph, and then a RNFLT report was generated based on the local images. Two indicators were designed based on the generated report. The support vector machines (SVM) algorithm was used to diagnose glaucoma based on the two indicators. Results:A strong correlation was found between the predicted and actual RNFLT values on local images. On three testing datasets, we found the Pearson r to be 0.893, 0.850, and 0.831, respectively, and the mean absolute error of the prediction to be 14.345, 17.780, and 19.250 μm, respectively. The area under the receiver operating characteristic curves for discriminating glaucomatous from healthy eyes was 0.860 (95 % confidence interval, 0.799-0.921). Conclusions:We established a novel local image-based DL approach to provide comprehensive quantitative information on RNFLT in fundus photographs, which was used to diagnose glaucoma. In addition, training a deep neural network based on local images to predict objective detail information in fundus photographs provided a new paradigm for the diagnosis of ophthalmic diseases.

PRÉCIS:Hypobaric hypoxia, the major environmental factor at high altitudes, has been observed to induce pupil miosis and widening of the anterior chamber angle. This environment may be safe for individuals with narrow angle and deserves further study. PURPOSE:This study aimed to quantify anterior chamber biometric parameters before and after acute short-term, effortless exposure to hypobaric hypoxia (HH) in healthy lowlanders using swept-source anterior segment optical coherence tomography (SS AS-OCT). METHODS:This prospective study included 25 healthy young lowlanders (50 eyes) who underwent SS AS-OCT measurements and intraocular pressure (IOP) assessments under baseline sea-level conditions (T1). They were then passively exposed to simulated 4000 m above sea level for 3 hours and underwent acute mountain sickness (AMS) symptoms evaluation and IOP measurement after 2 hours exposure to HH (T2). Repeat SS AS-OCT measurements and IOP assessments were taken within 15 minutes after leaving the hypobaric chamber (T3). Anterior segment parameters including anterior chamber depth (ACD), lens vault (LV), angle opening distance (AOD500), trabecular-iris space area (TISA500), angle recess area (ARA500) at 500 μm from the scleral spur, iris curvature (IC), iris volume (IV), pupil diameter (PD), and central corneal thickness (CCT) were obtained through SS AS-OCT. These repeated measurements were compared using linear mixed model analysis. RESULTS:In comparison to the sea level, both IOP (16.4±3.4 vs. 14.9±2.4 mm Hg, P =0.029) and PD (5.36±0.77 vs. 4.78±0.89 mm, P =0.001) significantly decreased after exposure to HH. Significant post-HH changes [mean difference (95% CI)] were observed in AOD500 [0.129 (0.006, 0.252), P =0.04], TISA500 [0.059 (0.008, 0.11), P =0.025], ARA500 [0.074 (0.008, 0.141), P =0.029], IV [1.623 (0.092, 3.154), P =0.038], and IC [-0.073 (-0.146, 0.001), P =0.047], whereas CCT, ACD, and LV remained stable. After adjusting for age, post-HH variations in AOD500 (Beta=0.553, 95% CI: 0.001, 1.105, P =0.048) and TISA500 (Beta=0.256, 95% CI: 0.02, 0.492, P =0.034) were associated with decreased IC but were not related to lowered arterial oxygen pressure or IV increase per millimeter of pupil miosis (IV/PD). These differences in anterior segment parameters were neither correlated with differences in IOP nor AMS. CONCLUSIONS:After short-term, effortless exposure to hypobaric hypoxia, pupil miosis occurred with widening of the anterior chamber angle and decreased IC. These changes in anterior chamber angle parameters were associated with decreased IC but did not correlate with the post-hypobaric variations in IV/PD, IOP, or AMS.

OBJECTIVE:To compare the efficacy and safety of ab interno canaloplasty (ABiC) with gonioscopy-assisted transluminal trabeculotomy (GATT) in patients with open-angle glaucoma (OAG). METHOD:This randomised clinical trial recruited eyes with OAG and no previous incisional ocular surgery, among which 38 were randomised to ABiC and 39 to GATT. Follow-ups were performed at 1, 3, 6 and 12 months postoperatively. The primary outcome measures were intraocular pressure (IOP) and use of glaucoma medication at 12 months postoperatively. The secondary outcome measure was complete surgical success (not requiring glaucoma surgery, IOP ≤21 mm Hg and non-use of glaucoma medications). RESULTS:Both groups had similar demographic and ocular characteristics. A total of 71 of the 77 subjects (92.2%) completed 12-month follow-up. At 12 months, mean IOP was 19.0±5.2 mm Hg in the ABiC group and 16.0±3.1 mm Hg in the GATT group (p=0.003). Overall, 57.2% of ABiC patients and 77.8% of GATT patients were medication free (p=0.06). The number of glaucoma medications was 0.9±1.3 in the ABiC group and 0.6±1.2 in the GATT group (p=0.27). The 12-month cumulative rate of complete surgical success was 56% in the ABiC group and 75% in the GATT group (p=0.09). Three eyes in the ABiC group and one eye in the GATT group required additional glaucoma surgery. Hyphema (87% vs 47%) and supraciliary effusion (92% vs 71%) were noted more often in the GATT group than in the ABiC group. CONCLUSIONS:The preliminary result showed that GATT had an advantage over ABiC in IOP reduction for OAG patients, accompanied by favourable safety at 12-month postoperatively. TRIAL REGISTRATION NUMBER:ChiCTR1800016933.

To compare the surgical effectiveness and safety of phacoemulsification combined with KDB (Phaco-KDB) and with Trabectome (Phaco-Trabectome) at 6 months follow-up in patients with open-angle glaucoma (OAG) This comparative case series was conducted at Beijing Tongren Hospital, including patients diagnosed with OAG who underwent Phaco-KDB from November 2021 to April 2022 and Phaco-Trabectome from April 2017 to December 2017. Surgical success was defined as an IOP reduction ≥ 20 What is known: • Both Phacoemulsification combined with Kahook Dual Blade Goniotomy (Phaco-KDB) and with Trabectome (Phaco-Trabectome) can reduce intraocular pressure (IOP) and the number of IOP-lowering medications in mid-term results. What is new: • KDB and Trabectome share similar mechanisms for IOP-lowering • In mid-term results, both Phaco-KDB and Phaco-Trabectome exhibit similar efficacy in reducing IOP, decreasing the numbers of IOP-lowering medications and achieving surgical success in Asian open angle glaucoma patients. • Phaco-Trabectome appears to provide more predictable postoperative course in the early postoperative period compared to Phaco-KDB and the postoperative mean IOP is lower in Phaco-KDB compared to Phaco-Trabectome, despite not being statistically significant. It will help clinicians to choose the optimal surgical interventions.

Objective:To compare the medium-term therapeutic effects of Kahook Dual Blade (KDB) goniotomy and Trabectome surgery in the treatment of patients with primary open-angle glaucoma (POAG).Methods:This study was a non-randomized prospective interventional controlled clinical study. POAG patients who underwent KDB goniotomy or Trabectome surgery at Beijing Tongren Hospital from May 2017 to April 2022 were enrolled. The definition of successful surgery was postoperative average intraocular pressure (IOP)≤21 mmHg (1 mmHg=0.133 kPa) and IOP decrease≥20%. Follow-up visits were conducted on the 1st day, 1st week, 1st, 3rd and 6th month after surgery. The IOP value, the number of IOP-lowering medications, the proportion of surgical success (average IOP≤21 mmHg at 6 months), and complications were evaluated. Statistical methods included independent sample t-test, Mann-Whitney rank sum test, χ2 test, repeated measures two-factor analysis of variance, Bonferroni, Friedman M test, Wilcoxon, and Log-rank. The Kaplan-Meier method was used to calculate the cumulative success rate of each group. Results:Seventeen male patients (17 eyes) and 10 female patients (10 eyes) were included. The mean age was (39.9±17.7) years old. There were 11 patients in the KDB group and 16 patients in the Trabectome group. There was no significant difference in clinical baseline conditions between the two groups ( P>0.05). The IOPs in the KDB and Trabectome groups at postoperative 1 week [(16.6±6.3) and (16.4±4.1) mmHg) and 6 months [(17.8±5.3) and (19.9±4.4) mmHg) were lower than those before surgery [(25.1±9.3) and (27.4±9.1) mmHg) (all P<0.05). There was no significant difference in the overall IOP between groups ( P>0.05). The IOP reduction rates in the KDB and Trabectome groups were 23.4% and 19.0%, with no significant difference ( P=0.674). The numbers of IOP-lowering medications used in the KDB and Trabectome groups at 3 months [2.0 (1.0, 4.0) and 2.0 (1.0, 2.3)] and 6 months [2.0 (0.0, 4.0) and 2.0 (1.0, 3.0)] after surgery were not significantly different from those before surgery [4.0 (2.0, 4.0) and 3.0 (2.0, 4.0)] (both P>0.05). There was no statistical significance in the overall number of IOP-lowering medications used between the two groups ( P>0.05). There was also no statistically significant difference in the proportion of patients with an IOP decrease of≥20% and the proportion of patients whose mean postoperative IOP was≤21 mmHg (all P>0.05). The proportions of IOP≤21 mmHg in the KDB group and the Trabectome group at 6 months after surgery were 81.8% and 68.8% ( P>0.05). Serious intraoperative or postoperative complications occurred in neither group. Conclusions:Both KDB trabeculotomy and Trabectome surgery can effectively reduce IOP and have a good safety profile in treating POAG, with the same number of IOP-lowering medications.

Background To evaluate the safety and efficacy of gonioscopy-assisted transluminal trabeculotomy (GATT) in treating patients with open-angle glaucoma (OAG) who had failed prior incisional glaucoma surgery. Methods A consecutive case series of OAG patients aged ≥ 18 who underwent GATT with previous failed glaucoma incision surgery was retrospectively analyzed. Main outcome measures included intraocular pressure (IOP), the number of glaucoma medications, surgical success rate, and occurrence of complications. Success was defined as an IOP of ≤ 21 mmHg and a reduction of IOP by 20% or more from baseline with (qualified success) or without (complete success) glaucoma medications. For eyes with preoperative IOP of < 21 mmHg on 3 or 4 glaucoma medications, postoperative IOP of ≤ 18 mmHg without any glaucoma medications was also defined as complete success. Results Forty-four eyes of 35 patients (21 with juvenile-onset open-angle glaucoma and 14 with adult-onset primary open-angle glaucoma) with a median age of 38 years were included in this study. The proportion of eyes with 1 prior incisional glaucoma surgery was 79.5%, and the others had 2 prior surgeries. IOP decreased from 27.4 ± 8.8 mm Hg on 3.6 ± 0.7 medications preoperatively to 15.3 ± 2.7 mm Hg on 0.5 ± 0.9 medications at the 24-month visit ( P < 0.001). The mean IOP and the number of glaucoma medications at each follow-up visit were lower than the baseline (all P < 0.001). At 24 months postoperatively, 82.1% of the eyes had IOP ≤ 18 mmHg (versus 15.9% preoperatively, P < 0.001), 56.4% reached IOP ≤ 15 mmHg (versus 4.6% preoperatively, P < 0.001), and 15.4% achieved IOP ≤ 12 mmHg (compared to none preoperatively, P = 0.009). While 95.5% of eyes took 3 or more medications preoperatively, 66.7% did not take glaucoma medication 24 months after GATT. Thirty-four (77.3%) eyes achieved IOP reduction greater than 20% on fewer medications. The complete and qualified success rates were 60.9% and 84.1%, respectively. No vision-threatening complications occurred. Conclusions GATT was safe and effective in treating refractory OAG patients who failed prior incisional glaucoma surgery.

Objective:To compare the efficacy and safety of trabeculotome tunnelling trabeculoplasty and gonioscopy-assisted transluminal trabeculotomy (GATT) in the treatment of open-angle glaucoma.Methods:A prospective randomized controlled study. The patients with open-angle glaucoma diagnosed in the ophthalmology center of Beijing Tongren Hospital affiliated to Capital Medical University from January to July 2022 were collected and divided into GATT group (undergoing GATT) and 3T group (undergoing 3T operation) using a random number table. Intraocular pressure (IOP) was recorded for both groups at 1 day, 1 week, 1 month, and 3 months after the operation, and the types and quantities of anti-glaucoma drugs used, postoperative complications, and surgical success rate were compared. Normal distribution measurement data were analyzed using independent sample t-tests, non-normal distribution measurement data were analyzed using non-parametric tests, and counting data were analyzed using chi-square tests. Results:This study included 35 patients (43 eyes), consisting of 27 males and 8 females, with an average age of (43.0±14.3) years. There were 21 patients (23 eyes) in the GATT group and 19 patients (20 eyes) in the 3T group. The maximum IOP without anti-glaucoma drugs before surgery, the highest IOP with the maximum number of anti-glaucoma drugs, and the IOP at 3 months after surgery in the GATT group were (33.5±9.1), (22.2±6.1), and (16.0±3.1) mmHg (1 mmHg=0.133 kPa), respectively. The corresponding values for the 3T group were (35.2±7.8), (21.5±6.8), and (16.1±2.0) mmHg. After surgery, the IOP in both groups was lower than before surgery, with a statistically significant difference ( P<0.05) and no significant difference between the two groups ( P>0.05). In the 3 months following surgery, 13 eyes in the GATT group and 11 eyes in the 3T group received more than two types of anti-glaucoma drugs, with no significant difference between the two groups ( P>0.05). Three months after surgery, the complete and conditional success rates of the GATT group were 14/18 and 16/18, respectively, and those of the 3T group were 12/15 and 13/15, respectively, with no significant difference between the two groups ( P>0.05). The incidence of hyphema, ciliary detachment, and shallow anterior chamber 1 day after surgery was 91%(21/23), 35%(8/23), and 30%(7/23), respectively, in the GATT group and 55%(11/20), 5%(1/20), and 0 in the 3T group, with a statistically significant difference between the two groups ( P<0.05). Conclusion:3T and GATT have similar success rates in the treatment of open-angle glaucoma. However, compared with GATT, 3T has fewer complications and is considered to be safer. (This article was published ahead of print on the Online-First Publishing Platform for Excellent Scientific Researches of Chinese Medical Association Publishing House on February 28, 2023)

BACKGROUND:Blood perfusion of the optic nerve (ON) plays a key role in many optic neuropathies. Microvascular changes precede or accompany neuronal changes, and detecting these changes at an early stage may facilitate early treatment to avoid blindness. However, the quantification of ON blood perfusion remains a challenge. This study aimed to evaluate the viability of three-dimensional pseudocontinuous arterial spin labelling (3D-pCASL) MRI for the quantification of ON blood flow (BF). NEW METHOD:The ON segmentation was performed using nnFormer on a cohort of ten participants (4 males, 6 females, 25-59 years old). Subsequently, the mean BF of each ON segment was calculated using whole brain 3D-pCASL image data. RESULTS:The average ON-BF values of the left and right intraorbital segments, left and right intracanalicular segments, left and right intracranial segments, optic chiasma, and left and right optic tract were 41.308 mL/100 g/min, 43.281 mL/100 g/min, 53.188 mL/100 g/min, 57.202 mL/100 g/min, 45.089 mL/100 g/min, 49.554 mL/100 g/min, 42. 326 mL/100 g/min, 43.831 mL/100 g/min and 45.176 mL/100 g/min, respectively. The ON-BF correlated with cerebral BF (r = 0.503, p = 0.024). COMPARISON WITH EXISTING METHOD(S):The 3D-pCASL can measure tissue microvascular blood perfusion in absolute quantitative units with good test-retest repeatability over a wide field of view and without restrictions on depth. The use of the nnFormer makes the measurement easy, objective and reproducible. CONCLUSIONS:The study showed that, 3D-pCASL may be a promising tool for detecting abnormal ON-BF. In particular, 3D-pCASL coupled with the nnFormer provides an objective, reproducible, and reliable method to quantify BF in ON.

Increased cerebral blood flow resulting from altered capillary level autoregulation at high altitudes leads to capillary overperfusion and then vasogenic cerebral edema, which is the leading hypothesis of acute mountain sickness (AMS). However, studies on cerebral blood flow in AMS have been mostly restricted to gross cerebrovascular endpoints as opposed to the microvasculature. This study aimed to investigate ocular microcirculation alterations, the only visualized capillaries in the central neural system (CNS), during early-stage AMS using a hypobaric chamber. This study found that after high altitude simulation, the optic nerve showed retinal nerve fiber layer thickening (P=0.004–0.018) in some locations, and the area of the optic nerve subarachnoid space (P=0.004) enlarged. Optical coherence tomography angiography (OCTA) showed increased retinal radial peripapillary capillary (RPC) flow density (P=0.003–0.046), particularly on the nasal side of the nerve. The AMS-positive group had the largest increases in RPC flow density in the nasal sector (AMS-positive, Δ3.21±2.37; AMS-negative, Δ0.01±2.16, P=0.004). Among multiple ocular changes, OCTA increase in RPC flow density was associated with simulated early-stage AMS symptoms (beta=0.222, 95

Purpose Primary open-angle glaucoma (POAG) is a widespread neurodegenerative condition affecting brain regions involved in visual processing, somatosensory processing, motor control, emotional regulation and cognitive functions. Cerebral hemodynamic dysfunction contributes to the pathogenesis of glaucomatous neurodegeneration. We aimed to investigate cerebral blood flow (CBF) redistributed patterns in visual and higher-order cognitive cortices and its relationship with clinical parameters in POAG, and we hypothesized that CBF changes together across regions within the same functional network. Methods Forty-five POAG patients and 23 normal controls underwent three-dimensional pseudocontinuous arterial spin labeling MRI to measure the resting-state CBF. Group comparisons of CBF and correlations between CBF changes and ophthalmological and neuropsychological indices were assessed. We determined CBF-based functional connectivity (CBFC) by calculating the correlations between specific regions and all other brain voxels and compared CBFC differences between groups. Results The patients exhibited decreased CBF in visual cortices, postcentral gyrus, inferior parietal lobule and cerebellum and increased CBF in medial, middle, and superior frontal gyri, as well as the insula. The reduced CBF in the visual cortices positively correlated with visual field defect ( r = 0.498, p = 0.001) in POAG patients, while the increased CBF in the right medial frontal gyrus was negatively associated with the visual field defect ( r = −0.438, p = 0.004) and positively associated with the cup-to-disc ratio ( r = 0.469, p = 0.002). POAG patients showed negative connections weakening or converting to mild positive connections, as well as positive connections converting to negative connections. Conclusions Regional and interregional CBF properties confirmed that the aberrant brain regions extend beyond the visual pathway, including the somatosensory, emotional and cognitive networks, which highlights the importance of cerebral hemodynamic dysfunction in the pathophysiology of spreading neurodegeneration in POAG.

Introduction: The aim of the study was to compare macular vascular microcirculation in early primary open-angle glaucoma (POAG), normal tension glaucoma (NTG), and normal subjects. Methods: 99 patients with early glaucoma (99 eyes: 60 POAG and 39 NTG) and 78 normal subjects were included. All subjects underwent optical coherence tomography angiography scan at 6 × 6 mm macular area. Macular vessel density (VD) and perfusion density (PD) and 9 sectors were compared between the controls, POAG, and NTG groups. Linear regression analysis was used to investigate the relationship between VD and other variables including macular PD, signal strength (SS), and mean macular ganglion cell-inner plexiform layer (mGCIPL) thickness. Results: Significant losses in total area of VD and PD were detected in POAG and NTG groups compared to the controls (all p < 0.01). There were no significant differences in all inner sectors of macular VD and PD between POAG and controls (all p > 0.05). Except for outer-nasal sector, all other outer sectors of macular VD and PD were significantly lower in POAG than in the controls (all p < 0.01). The inferior-inner sector and all outer sectors of VD and PD were significantly lower in NTG than in the controls (all p < 0.01). Macular VD was significantly correlated with macular PD (r = 0.99, p < 0.001), SS (r = 0.60, p < 0.001), and mGCIPL thickness (r = 0.51, p < 0.001). Conclusions: Macular microcirculation declined significantly in early POAG and NTG patients. Macular microcirculation loss in the NTG group was more central and nasal compared with that in the POAG group. A decrease in macular VD was correlated with lower macular PD, lower SS, and thinner mGCIPL thickness.

Glaucoma is the leading cause of irreversible blindness worldwide. Currently the only effective treatment for glaucoma is to reduce the intraocular pressure, which can halt the progression of the disease. Highlighting the importance of identifying individuals at risk of developing glaucoma and those with early-stage glaucoma will help patients receive treatment before sight loss. However, some cases of glaucoma do not have raised intraocular pressure. In fact, glaucoma is caused by a variety of different mechanisms and has a wide range of different subtypes. Understanding other risk factors, the underlying mechanisms, and the pathology of glaucoma might lead to novel treatments and treatment of underlying diseases. In this review we present the latest research into glaucoma including the genetics and molecular basis of the disease.

Delineating the neuropathological characteristics of primary open-angle glaucoma (POAG) is critical for understanding its pathophysiology. While temporal stability represents a crucial aspect of the brain's functional architecture, the specific patterns underlying its contribution to POAG remain unclear. This study aims to analyze the brain functional abnormalities in POAG using functional stability, a dynamic functional connectivity (DFC) approach based on resting-state functional magnetic resonance imaging (rs-fMRI). Seventy patients with POAG and forty-five healthy controls underwent rs-fMRI and ophthalmological examinations. The stability of DFC was calculated as the concordance of DFC over time using a sliding-window approach, and the differences in stability between the two groups were compared. Subsequently, Spearman’s correlation analyses were conducted to examine the relationship between functional stability and clinical indicators. Compared with healthy controls, patients with POAG exhibited significantly decreased functional stability in the visual network, including the early visual center, ventral and dorsal stream visual cortex in both hemispheres. Conversely, stability values increased in the bilateral inferior parietal gyrus and right inferior frontal cortex. In POAG patients, the dynamic stability of the left early visual cortex and ventral stream visual cortex correlated with the mean deviation of visual field defects ( r = 0.251, p = 0.037). The evidence from this study suggests that functional stability may provide a new understanding of brain alterations in the progression of POAG.

The rising global prevalence of myopia is a growing concern for clinicians, as it predisposes patients to severe ocular pathologies including glaucoma. High myopia can be associated with clinical features that resemble glaucomatous damage, which make an accurate glaucoma diagnosis challenging, particularly among patients with normal intraocular pressures. These patients may also present with established visual field defects which can mimic glaucoma, and standard imaging technology is less useful in disease detection and monitoring due to the lack of normative data for these anatomically unique eyes. Progression over time remains the most critical factor in facilitating the detection of early glaucomatous changes, and thus careful longitudinal follow-up of high-risk myopic patients is the most important aspect of management. Here, we review our current understanding of the complex relationship between myopia and glaucoma, and the diagnostic challenges and limitations of current testing protocols including visual field, intraocular pressure, and imaging. Furthermore, we discuss the clinical findings of two highly myopic patients with suspected glaucoma.